The impact of gestational age on perioperative morbidity was examined using a novel construct, the resource utilization index (RUI). The medical records of subjects from birth to 1 year of age entered into a pediatric cardiothoracic surgery database from a major academic medical center between 2007 and 2011 were reviewed. The hypothesis tested was that infants born at 37-38 weeks (early-term infants) experience greater resource utilization after open heart surgery than those born at 39 completed weeks and that this association can be observed until 1 year of age. The results support the premise that resource utilization increases linearly with declining gestational age among infants at 0-12 months who undergo cardiac surgery. Five of the six variables comprising the RUI showed statistically significant linear associations with gestational age in the predicted direction. Multivariate linear regression analysis showed that gestational age was a significant predictor of an increased RUI composite. Further investigation is needed to test the concept and to expand on these findings.